Slugs and snails are capable of causing substantial damage to ornamental plants and agricultural crops. Slugs and snails are omnivorous and find leaves, bulbs, tubers, fungi, ligands, algae and animal matter very attractive for consumption. Agricultural crops such as leafy vegetables, green beans and strawberries can be extensively damaged by molluscs. Also fruit and fruit trees can be extensively damaged by the foraging creatures. Livestock feed crops, such as hay and clover can also be extensively damaged by molluscs. Tests have shown that a slug or snail can consume its own weight in food in a matter of days. In addition to damaging or killing plant life, many homeowners find the physical appearance of slugs and snails objectionable.
If uncontrolled, slugs and snails can reproduce rapidly, resulting in an exponential increase in damage to horticultural and agricultural plant life. Because slugs and snails are semi-nocturnal, they often avoid capture by their natural predators, including birds, that generally actively feed only during the daylight hours.
The substance metaldehyde has been used to control slug and snail populations. When the slugs or snails either ingest or contact metaldehyde, the metaldehyde induces a brief period of paralysis followed by stimulation of the mucous secreting glands in the slugs or snails. Such stimulation of the mucous secreting glands results in the production of excessively large quantities of a viscid slime. Excessive slime production, in combination with the desiccating effect of exposure to sunlight during daylight hours causes the slugs to die by dehydration. Known molluscicides to control slug and snail populations commonly combine metaldehyde or another composition lethal to molluscs with a dry particulate material that serves to carry the poison and/or act as an attractant for the slugs and snails. Alternatively, the poison and particulate material are formed into pellets for convenient application. Such known molluscicides, commonly known as dry bait, suffer from several disadvantages. For example, water from precipitation or irrigation tends to wash away or dilute the bait at the point of application. In addition, the water can cause the poison to become detached from the carrier material and be washed into the soil where it will not be effective against snails and slugs unless they burrow into the soil and come into contact with or ingest the poison. Also, if the dry bait is applied under relatively low humidity conditions or low moisture conditions, it can be blown away. Finally, because the carrier for the poison is often an organic material, when exposed to moisture and heat at the point of application, the organic material tends to mold and decompose, leaving an unsightly residue.
Weatherproof types of baits or poisons have been developed. For example, in U.S. Pat. No. 2,363,852, finely divided metaldehyde is distributed throughout a weatherproof or weather resistant body produced from paraffin oil. The '852 patent also describes that various attractants can be added to the combination of the paraffin oil and metaldehyde. Another type of weatherproof poison includes an oil-based emulsion as a vehicle for delivering the poison to the point of application. Unfortunately, previous weatherproof types of baits are either less effective than desired and/or still susceptible to erosion by water during extended periods of precipition or irrigation. Further, the oil-based carriers can be difficult to handle during production and tend to lose their palatable texture after extended periods of exposure to outdoor conditions. Finally, weatherproof types of baits that employ oil-based carriers introduce hydrocarbon derivatives into the environment as the bait erodes.
It would be desirable to provide a weatherproof type of pesticide composition that kills pests effectively without endangering other types of plant and animal life that may come into contact with the pesticide. The pesticide composition should be resistant to environmental conditions, such as water and wind, and yet should be safe to introduce into the environment.